The invention is of particular application to the synthesis of compounds from at least two elements of which at least one is a metal and particularly to the group III-V and group II-VI compounds, at least one component of which has appreciable vapour pressure at temperatures at and approaching that at which reaction occurs leading to the formation of such compounds. The groups referred to are those of a periodic table according to Mendeleef.
The invention is not limited to compounds such as those described but is equally applicable to the formation of ternary and quarternary compounds, to mixed group III and V compounds as well as to group II-IV-V compounds.
With the development of light emitting diodes and infra-red transmission devices, interest has continued to develope in the formation of group III-V and group II-VI compounds such as Gallium Phosphide, Indium Phosphide, Gallium Arsenide, Zinc Selenide and Cadmium Telluride.
Many of the components of these materials have very high vapour pressures at elevated temperatures. This means that although the principal difficulties of producing single crystals from the poly crystalline materials have been largely overcome by the use of liquid encapsulated crystal growing techniques, the excessive cost of producing the poly crystalline compounds in the first place has materially hindered single crystal manufacture and use.